1. Field of the Invention
The present invention relates to an endoscope apparatus, and more particularly, to an endoscope apparatus that controls a movable lens of an observation optical system provided in a tip portion of an endoscope insertion part.
2. Description of the Related Art
As well known, an endoscope apparatus (endoscope system) includes an endoscope (scope) that comprises an imaging section for imaging the inside of a body cavity, a processor device that performs image processing on image data taken by the imaging section of the endoscope and output from the endoscope and outputs the image data to a display device, and the like.
JJP4127731B discloses an endoscope that employs a zoom optical system of which a focal length can be changed by the movement of a part (zoom lens) of the lenses in the direction of an optical axis as an objective optical system of an imaging section of an endoscope and can change the magnification (zoom magnification) of an observation image taken by the imaging section.
According to JP4127731B, the endoscope includes a zoom switch that is used by a user to instruct the zoom magnification of the observation image to be changed, and the zoom switch includes a wide-side switch that instructs the zoom magnification to be changed to a wide side (a low-magnification side), and a telephoto-side switch that instructs the zoom magnification to be changed to a telephoto-side (a high-magnification side).
The zoom lens of the zoom optical system is moved to the wide side or the telephoto side by a predetermined distance when drive pulses are supplied to an actuator connected to the zoom lens, and the position of the zoom lens is controlled by the number of drive pulses supplied to the actuator. Further, JP4127731B discloses that various modes are provided for the control of the zoom lens, drive pulses of which the number is predetermined are supplied to the actuator in a user's on-operation of the telephoto-side switch or the wide-side switch of the zoom switch in a step mode that is one among the modes, and the zoom lens is moved to a position where a predetermined specific zoom magnification (one time, 20 times, 40 times, 60 times, . . . ) is obtained.